Disk drive breather filter

A chemical filter system for excluding pollutants from an electronic equipment enclosure comprising

• an opening through a wall forming said enclosure;
• a housing mounted in said opening and sealed to said wall;
• a multiple layer filter medium enclosed by said housing and positioned to be in the path of all air entering or exiting said enclosure through said opening;
• said multiple layer filter medium including a particulate prefilter layer, a particulate final filter layer and an intermediate chemical filter layer;
• a first extended length diffusion passage means extending from the exterior of said enclosure to said prefilter;
• and
• a second extended length diffusion passage means extending from said final filter to the interior of said enclosure.

A chemical filter system for excluding pollutants from a head disk enclosure of a magnetic disk data storage device comprising

• an opening through a wall forming said enclosure;
• a housing carried by said enclosure wall at said opening and sealed to said wall;
• a multiple layer filter medium enclosed within said housing and positioned to be in the path of all air entering or exiting through said opening;
• said multiple layer filter medium including a chemical filter means for entrapping organic chemical vapors;
• a first extended length diffusion passage means extending from the exterior of said enclosure to one side of said filter medium;
• and
• a second extended length diffusion passage means extending from the side of said filter medium opposite said one side to the interior of said enclosure.

A chemical filter system for excluding pollutants from an electronic equipment enclosure comprising

• an opening through a wall forming said enclosure;
• a housing carried by said enclosure at said opening;
• a multiple layer filter medium enclosed within said housing and positioned to be in the path of all air entering through said opening;
• said multiple layer filter medium including a particulate filter and a chemical filter means for entrapping organic chemical vapors;
• a first extended length diffusion passage means extending from the exterior of said enclosure to adjacent one side of said filter medium;
• a second extended length diffusion passage means extending from the side of said filter medium opposite said one side to the interior of said enclosure;
• a first chamber adjacent said one side of said filter medium to which said first extended length diffusion passage means connects;
• and
• a second chamber adjacent the side of said filter medium opposite said one side to which said second extended length diffusion passage mans is connected;
• one of said first and second extended length diffusion passage means communicating with the associated chamber at multiple locations adjacent the periphery of the adjoining filter medium and the other of said first and second extended length diffusion passage means communicating with the associated chamber adjacent the center of the adjoining filter medium.